I really respect food bloggers who come up with their own recipes. I rarely create my own recipes because I’m just too lazy and busy to perfect an original dish before posting it on this blog. That’s why I love the folks at Cook’s Illustrated because they do all the testing and retesting for me. As a result, their recipes are normally fail-proof on my first attempt.
I cobbled together a respectable roasted portobello mushroom recipe a while back but this recipe from The Best Vegetable Recipes cookbook kicks ass. You do need to allow time to marinate the caps but it’s totally worth it. The original recipe calls for grilling the mushroom packets but I just stuck them in a hot oven. This is a fantastic dish for entertaining because you can make it ahead and serve it at room temperature.
Time to make Roasted Portobello Mushroom Packets with Lemon and Garlic!
Serves 3
Ingredients:
- ½ cup avocado oil (the original recipe uses extra virgin olive oil)
- 3 tablespoons juice from 1 lemon
- 6 medium cloves of garlic, pressed through a garlic press
- ½ teaspoon Kosher salt
- 1 tablespoon of Fines Herbes seasoning
- 3 large portobello mushrooms, gills and stems removed, caps wiped clean (there’s enough marinade for 4 large caps or 5 medium caps)
Equipment:
- All of my recommended kitchen tools are listed here.
Method:
I preheated the oven to 400 F and I prepared the mushroom caps.
I’m a big fan of removing the gills because your ‘shrooms won’t look all muddy when they’re finished.
I mixed up the marinade by combining the avocado oil, lemon juice, garlic, herbs, and salt in a large Ziploc gallon bag.
I added the mushrooms to the marinade and let them sit for an hour.
When the time was up, I removed the caps from the marinade and wrapped each one in a large piece of foil…
…and placed them on a foil-lined baking tray.
I placed the tray in the oven for 25 minutes and when they were finished, I let the caps rest in the foil packets for 10-15 minutes.
(If you decide to cook these packets on the grill, place them seam side up on a medium hot flame for 10-12 minutes.)
I sliced up the mushrooms and used the reserved juices as a sauce.
These roasted ‘shrooms are delicious and tasty!
Looking for more recipe ideas? Head on over to my Recipe Index. You’ll also find exclusive recipes on my iPhone and iPad app, and in my cookbooks, Nom Nom Paleo: Food for Humans (Andrews McMeel Publishing 2013), Ready or Not! (Andrews McMeel Publishing 2017), and Nom Nom Paleo: Let’s Go! (Andrews McMeel Publishing 2021).
PRINTER-FRIENDLY RECIPE CARD
Roasted Portobello Mushroom Packets with Lemon and Garlic

Ingredients
- ½ cup avocado oil
- 3 tablespoons lemon juice
- 6 garlic cloves pressed through a garlic press
- 1 tablespoon Fines Herbes seasoning
- ½ teaspoon Diamond Crystal kosher salt
- 3 large Portobello mushrooms gills and stems removed, caps wiped clean
Instructions
- Begin prepping the mushroom caps by removing the stems and gills.
- Time to start the marinade! Combine avocado oil, lemon juice, garlic, seasoning, and salt in a large Ziploc gallon bag.
- Add the mushrooms to the marinade and let them sit for an hour.
- Preheat the oven to 400°F a bit before the hour is done. Remove the caps from the marinade and wrap each one in a large piece of foil and place on top of a foil-lined baking tray.
- Place the tray in the oven for 25 minutes. Take the ray out of the oven and let the caps rest in their foil packets for another 10-15 minutes.
- Slice up the mushrooms and use the reserved juices as a sauce!
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.